The Emissions Control Project at CPB will
result in significant emission reductions of SO2 and NOx. Further reduction in particulate emissions is also
anticipated as a result of SO2 emission control in addition to existing high efficiency ESP.
The construction and operation of the Project could
also result in some environmental impacts which have been the subject of a
detailed assessment under this Study.
They are summarised and discussed in the following sub-sections.
11.1
Air
Quality
11.1.1
Construction Phase
Dust from excavation, site formation and construction
activities is the only key air quality concern during the construction of the
Project. Owing to the small scale
of the civil construction requirement and the distance from the ASRs, no
adverse dust impact is anticipated.
In addition, only a limited number of diesel-powered equipment will be
operated on site, and therefore impact from construction equipment is expected
to be minimal. With the
implementation of the dust control measures stipulated in the Air Pollution Control (Construction Dust)
Regulation, no adverse air quality impact is envisaged from the
construction of the Project.
11.1.2
Operational Phase
Except for a slight
increase of emissions associated with marine traffic due to increased reagent
and by-product transportation, the operation of the Project will not introduce
any additional emissions of air pollutants, while the SO2 and NOx emissions will be significantly reduced.
The following reduction efficiencies
are used as the basic assumptions for the operational air quality assessment:
·
SO2
emission reduction by up to 90%; and
·
NOx
emission reduction by up to 80%.
A comparative air quality assessment was
conducted for CPB by scale model testing performed in a Boundary Layer Wind
Tunnel to simulate the behaviour of the exhaust plume before and after
installation of the proposed emission control equipment.
The
modelled percentage reduction in SO2 and NOx
concentrations at the 36 ASR locations after implementation of the retrofit
programme are similar in magnitude to the proposed emission reductions at
source. The effects of changes in
flue gas characteristics on the dispersion of emissions were minor and
insignificant when compared to the corresponding reductions in SO2
and NOx emissions from CPB after retrofit.
The comparative
study demonstrated that all the identified ASRs will have an improvement in air
quality after the retrofit as required in Section
3.4.1.2 of the Study Brief.
11.2
Noise
11.2.1
Construction Phase
The construction noise assessment conducted for the
Project indicates that the predicted noise levels at the noise sensitive
receivers (NSRs) are expected to range from 43 to 51 dB(A) and therefore within
the noise criteria. This is due
mainly to the considerable separation distance and the screening offered by the
topography and the existing buildings.
In view of the assessment results, the noise generated during the
construction phase is not expected to cause any adverse impact and mitigation
measures will not be required.
11.2.2
Operational Phase
The noise levels at the identified NSRs (Sha Po
Kong village and the planned holiday camp at Siu Lang Shui) from the operation
of the Project have been predicted based on the specified maximum sound
pressure levels (SPL) for the new equipment to be installed at CPB. The results indicate that the identified
NSRs will be subject to noise levels of up to 35 dB(A), which complies with
both the stipulated daytime and night-time noise criteria.
The suppliers of the new equipment should guarantee
the specified SPL by providing certificate of measurement and
verify the SPL during testing and commissioning in accordance with
international standard procedures.
If necessary, the suppliers should apply attenuation measures to achieve
the guaranteed noise levels during the detailed design stage. With the noise specifications in place,
further mitigation measures will not be required during the operational phase
of the Project.
11.3
Water
Quality
11.3.1
Construction Phase
The water quality modelling works, with the assumption of no mitigation
measures to be adopted, have indicated that for both the dry and wet seasons,
no exceedances of the WQO and the evaluation criterion are predicted to occur
during the dredging operations. The
impact assessment has also shown that other land-based construction works, if
properly controlled, are not expected to cause any adverse impacts to the
surrounding waters and the sensitive receivers.
11.3.2
Operational Phase
No effluent is anticipated from the operation of the NOx control
system and water quality impact is not expected.
In the LS-FGD process, the gypsum slurry from the absorber unit is
treated, resulting in dewatered gypsum and a small quantity of liquid
effluent. The resulting effluent
may have a small chemical oxygen demand and/or reduced dissolved oxygen
concentrations.
The effluent will be treated to comply with the discharge standards
stipulated in the Technical Memorandum on
Standards for Effluents Discharged Into Drainage And Sewerage Systems, Inland
And Coastal Waters issued under the Water
Pollution Control Ordinance. It
will then be added to the cooling water flows and discharged via the existing
sub-marine cooling water outfall of CPB, resulting in a small increase (about
0.02%) in the total flows from the outfall. The treated FGD effluent would not be
expected to have any adverse effect on the temperature of the cooling water or
on the quantities of residual chlorine in the discharge. The high degree of mixing inherent in
the coastal margin or coastal zone will result in rapid dilution of the
effluent to very low concentrations and no exceedance of the WQO or evaluation
criteria for DO, dissolved metals, temperature, SS, salinity and sulphate are
expected. As a result, further
mitigation measures are considered unnecessary.
11.4
Waste
Management
11.4.1
Construction Phase
The key potential impacts
during the construction phase are related to management of dredged sediments,
demolition materials, excavated materials and construction waste.
About 80,700 m3
of uncontaminated sediment will be dredged to be disposed of at an open
sea. The final disposal site will
be determined by the MFC and a dumping licence will be obtained from EPD prior
to the commencement of the dredging works.
An estimated 50 m3
of potentially contaminated soil within the Project boundary will be treated
and disposed of in accordance with the Remediation Action Plan (RAP).
A total of about 835 tonnes
of scrap steel will be produced during demolition of oil tanks and the
associated fixtures/ appendages.
All the scrap steel will be delivered off-site by barge/truck for
recycling.
A total of about
30,000 m3 of excavated soil will be generated from the demolition
and construction works. All
excavated soil will be reused for the backfilling on-site.
Small quantities of
chemical wastes (less than 100 litres per month), sewage (a maximum of 135 m3
per day) and general refuse (a maximum of 585 kg per day) will be generated
during the construction phase.
With the implementation of
the mitigation measures recommended, the potential environmental impacts
arising from storage, handling, collection, transport and disposal of wastes
should be able to meet the criteria specified in the EIAO-TM. No adverse
waste management impact is anticipated.
11.4.2
Operational Phase
About 240,000 tonnes of commercial grade gypsum will
be generated each year from the FGD process and can be commercially recycled in
PRD and
With the implementation of the recommended
mitigation measures, the potential environmental impacts associated with the
storage, handling, collection, transport and disposal of a small quantity of
industrial waste and general refuse arising from the operation of the Project
will meet the criteria specified in the EIAO-TM
and no adverse waste management impact is anticipated.
11.5
Land
Contamination
A number
of existing facilities at CPB, including the FODT, the DG Store, the IPRS, the
LPG compound and the CO2 tanks, are required to be demolished to
accommodate the proposed emissions control equipment. A land contamination assessment was
carried out at these areas following the methodology and procedures prescribed
in the Contamination Assessment Plan (CAP) approved by the EPD. The land contamination assessment
included soil and groundwater sampling, laboratory analyses for target
parameters, preparation of Contamination Assessment Report (CAR) and
preparation of Remediation Action Plan (RAP).
With the implementation of
the remedial measures in the RAP, the hazard and environmental impacts
associated with the potential land contamination and handling and treatment of
the contaminated soil and groundwater are considered very low.
11.6
Ecology
The land-based construction works and operations of the
Project will be conducted entirely within the existing industrial site of CPPS
and therefore no impact on terrestrial ecology is envisaged.
The literature review of the existing marine ecological resources of the
Study Area identified two key sensitive receivers, namely the Sha Chau and
The predicted alterations of the water quality parameters attributable
to construction and operational activities are not expected to cause
exceedances of the WQO, and therefore no impacts to the marine ecological resources
or marine mammals are anticipated.
Mitigation measures designed to minimise impacts to the population of
Indo-pacific humpback dolphins that use the area include restrictions on vessel
speed while adopting local construction practice of using bubble curtains/jacket during percussive piling work for the
construction of the additional berthing facility. Other mitigation measures designed to
mitigate impacts to water quality to acceptable levels (compliance with WQOs)
are also expected to mitigate impacts to marine ecological resources.
11.7
Landscape
and Visual Considerations
With the new structures of the emissions control
equipment located within the existing industrial setting of CPB, the Project is
not expected to result in any negative impact on the surrounding landscape and it
will also have a very low visibility.
11.8
Conclusion
The Emissions Control Project at CPB will result in
significant emission reductions of SO2 and NOx. Further reduction in particulate emissions is also
anticipated as a result of the LS FGD operation.
The detailed impact assessment concluded that no
adverse environmental impacts are envisaged in the areas of air and water
quality, noise, waste management, land contamination, ecology and visual
appearance during both the construction and operational phases.